Switching systems are used to provide telecommunications services between two or more user interfaces. User interfaces may include telephone handsets, facsimile machines, computers, and other equipment, and may be connected to the switching system by fixed land-based conductors or wireless services. Telecommunications services are provided by establishing a telecommunications channel between two user interfaces, such that encoded analog or digital data may be transmitted between the user interfaces until reaching a state of completion.
Switching system reliability is an important characteristic of switching systems. Loss of the switching system can result in loss of revenues, customer dissatisfaction, and possibly injury or death if the switching system failure prevents emergency services from being summoned or dispatched in a timely manner.
To improve switching system reliability, it is common to use redundant components, such that a single component failure will not result in system unavailability. Nevertheless, known methods for controlling redundant components may result in an unacceptable system response during system startup. This condition arises because one of two or more redundant components must be selected as the primary component. If selection of the primary component is based on a polling technique, the system may become locked up if all components attempt to simultaneously respond to the poll. Alternatively, if one component is permanently assigned primary status, that component might be unable to receive back-up data from the secondary or lower status components. Thus, in the event that the primary component is taken out of service, the entire system must be taken out of service in order to reinitiate operation with the primary component.